I'm in linux and experienced that a double click triggers a normal single click as well. So if i double right click on my icon it hides the windows (= single right click in my configuration) and opens the new todo windows (= double right click) instead of only opening the window.

I think this is wrong. It's easy to wait a specified amount of time after a single click to see if another click occurs. If yes, it's a double-click event and if not it's a single click. In GUI-Frameworks like Swing or others it's done that way. Should be possible as far as i know.

Yes, you can do such things with a timer but at least in Windows the double click delay can be changed by the user. I think the maximum time is ~1 sec and that's too long time to wait before the application can react to the single clicks since it'll make it feel sluggish.

One possibility would be to implement this kind of delay only in the situation where an action is defined for both single and double clicks. I can consider this but don't expect it to be yet in the next version.